#include <bits/stdc++.h>
using namespace std;
int main(){
	int a1,a2,b1,b2,c1,c2,d,a3,b3,c3;
	cin>>d>>a1>>a2>>b1>>b2>>c1>>c2;
	if(d%a1==0) a3=d/a1;
	else a3=d/a1+1;
	if(d%b1==0) b3=d/b1;
	else a3=d/b1+1;
	if(d%c1==0) c3=d/c1;
	else a3=d/c1+1;
	int r=min(a3*a2,b3*b2);
	int q=min(r,c3*c2);
	cout<<q;
	
	return 0;
}